Multi-entity aggregation API (to be dicussed)

[fgalan]

It has been proposed by some users to have multi-entity aggregation API. That is, instead of aggregating on an attribute of a single entity, aggregate on an attribute of a set of entity (i.e. all the entities of a given type or a list of entities).

The implication has to be analyzed in order to decise if makes sense to have an operation like that. Performance penalty could be a reason for not doing so.

[mrutid]

Along with STH /notify endpoint, remark Cygnus dependencies (in production scenarios Cygnus is in charge of provision STH Data model). So two solutions are needed.

It's also interesting to think about the necessity to "name" someway the aggregation itself, so I can ask for it, this would imply the need to implement a create aggregation api. This naming is automatic nowadays, you just need to make the right subscription.

Default integration by Type could be feasible and don't need a creation step... probably it's good enough.

[antont]

I was googling for info about making multi entity queries to comet sth. Would be handy to get for example a certain attribute, or a set of attributes, for a given time, even just single values with a raw data query. Unless it's fine just to do n per entity queries for that.

I don't know about the input side, whether indeed the multi entity perspective should be taken into account there already, or could work for my case just when making a query. Have not made the data feeding side or anything with the servers in the project we are working on, we (at Playsign) are just using servers that folks in the CityIoT project at the University of Oulu have set-up and worked on to improve.